It is known to integrate two (or more) chips in one system for performing complex operations. For example, a modem chip and a separate application processor chip may each be included in a system. The microprocessor and the modem may each have associated SRAM, flash memory, SDRAM, etc. Accordingly, the two devices may each need respective dedicated interfaces to the SRAM, flash memory, SDRAM, etc., thereby increasing the cost of the system due to the dedicated SRAM, flash memory, SDRAM, devices for each.
In order to make one chip (e.g., a master chip) use resources of another chip (e.g., a slave chip), pins for bus protocol signals can be placed so as to be accessible outside the chip so that the bus protocol used inside the slave chip may be accessed from outside the slave chip. The bus protocol inside the chip may be designed only for a use inside the chip, such that the size of the address or data bus used therein is increased and the control signals may be more complicated. Thus, the number of pins used in the chip (the master chip) may increase. For example, the number of address pins needed from the master are in proportional to the memory size of the slave chip, and the same number of control pins as the number of control signals for the slave chip may also be needed. The increased number of pins may reduce the level of integration of a product, which may increase costs.